17ß-estradiol Attenuates the Middle Ear Inflammatory Response to Nontypeable Haemophilus influenzae.

OBJECTIVES: 17ß-estradiol (E2) is a steroidal hormone with immunomodulatory functions that play a role in infectious and inflammatory diseases. E2 was recently identified as the leading upstream regulator of differentially expressed genes in a comparative RNA sequencing study of pediatric patients with otitis media (OM) versus OM-free counterparts and may therefore play a role in the inflammatory response to bacterial otopathogens during pediatric OM. This study examined the effect of E2 on bacterial-induced inflammatory cytokine expression in an in vitro pediatric OM model. METHODS: An immortalized middle ear (ME) epithelial cell line, ROM-SV40, was developed from a pediatric recurrent OM patient. The culture was exposed to E2 at physiological levels for 1-48 h prior to 6 h-stimulation with nontypeable Haemophilus influenzae (NTHi) whole cell lysate. TNFA, IL1B, IL6, and IL8 were assayed by qPCR and ELISA. RESULTS: E2 pretreatment (24 h) abrogated NTHi induction of IL6; a longer pretreatment (1-10 nM, 48 h) abrogated IL1B induction (p < 0.05). E2 pretreatment (5 nM, 48 h) abrogated NTHi-induced IL8 secretion (p = 0.017). CONCLUSION: E2 pretreatment partially rescued NTHi-induced cytokine production by ME epithelia. These data support a role for E2 in moderating the excessive inflammatory response to middle ear infection that contributes to OM pathophysiology. LEVELS OF EVIDENCE: NA Laryngoscope, 134:3815-3819, 2024.

Longitudinal optical coherence tomography to visualize the in vivo response of middle ear biofilms to antibiotic therapy.

Studying the impact of antibiotic treatment on otitis media (OM), the leading cause of primary care office visits during childhood, is critical to develop appropriate treatment strategies. Tracking dynamic middle ear conditions during antibiotic treatment is not readily applicable in patients, due to the limited diagnostic techniques available to detect the smaller amount and variation of middle ear effusion (MEE) and middle ear bacterial biofilm, responsible for chronic and recurrent OM. To overcome these challenges, a handheld optical coherence tomography (OCT) system has been developed to monitor in vivo response of biofilms and MEEs in the OM-induced chinchilla model, the standard model for human OM. As a result, the formation of MEE as well as biofilm adherent to the tympanic membrane (TM) was longitudinally assessed as OM developed. Various types of MEEs and biofilms in the chinchilla model were identified, which showed comparable features as those in humans. Furthermore, the effect of antibiotics on the biofilm as well as the amount and type of MEEs was investigated with low-dose and high-dose treatment (ceftriaxone). The capability of OCT to non-invasively track and examine middle ear conditions is highly beneficial for therapeutic OM studies and will lead to improved management of OM in patients.

Suppression of lncRNA MALAT1 Reduces LPS- or IL-17A-Induced Inflammatory Response in Human Middle Ear Epithelial Cells via the NF-κB Signaling Pathway.

Otitis media (OM) is a common inflammatory disease of the middle ear cavity and mainly occurs in children. As a critical regulator of inflammation response, the nuclear factor kappa B (NF-κB) pathway has been found to play an essential role in the pathogenesis of various human diseases. The aim of this study was to explore the potential mechanism under the inflammatory response of human middle ear epithelial cells (HMEECs). We established in vitro models of OM by treating HMEECs with lipopolysaccharide (LPS) or interleukin 17A (IL-17A). Enzyme-linked immunosorbent assay and western blot analysis were used to measure the inflammatory response of HMEECs under LPS or IL-17A stimulation. The results revealed that the concentrations of proinflammatory cytokines (p < 0.001) and protein levels of mucin (MUC) (for MUC5AC, p = 0.002, p = 0.004; for MUC8, p = 0.004, p < 0.001) were significantly elevated by LPS or IL-17A stimulation in HMEECs. Moreover, we found that LPS or IL-17A treatment promoted the phosphorylation of IκBα (for p-IκBα, p = 0.018, p = 0.002; for IκBα, p = 0.238, p = 0.057) and the translocation of p65 from cytoplasm to nucleus in HMEECs (for nucleus p65, p = 0.01; for cytoplasm p65, p < 0.001). In addition, RT-qPCR analysis revealed that long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was verified to be upregulated in LPS- or IL-17A-stimulated HMEECs (p < 0.001). Western blot analysis and immunofluorescence staining assay revealed that that MALAT1 knockdown significantly suppressed the activation of the NF-κB pathway by reducing phosphorylated IκBα levels and inhibiting the nuclear translocation of p65 (p < 0.001) in LPS- or IL-17A-stimulated HMEECs (for p-IκBα, p < 0.001; for IκBα, p = 0.242, p = 0.647). Silence of MALAT1 decreased the proinflammatory cytokine production and MUC protein levels (p < 0.001). Furthermore, rescue assays revealed that the increase of proinflammatory cytokine production (for TNF-α, p = 0.002, p = 0.015; for IL-1ß, p < 0.001, p = 0.006; for IL-6, p = 0.002, p < 0.001) and MUC protein levels (for MUC5AC, p = 0.001, p < 0.001; for MUC8, p < 0.001, p = 0.001) induced by MALAT1 overexpression was neutralized by 4-N-[2-(4-phenoxyphenyl) ethyl] quinazoline-4, 6-diamine (QNZ) treatment in LPS- or IL-17A-stimulated HMEECs. In conclusion, MALAT1 promotes inflammatory response in LPS- or IL-17A- stimulated HMEECs via the NF-κB signaling pathway, which may provide a potential novel insight for the treatment of OM.

Transcriptomic analysis of tobacco-flavored E-cigarette and menthol-flavored E-cigarette exposure in the human middle ear.

Electronic cigarettes (e-cigarettes) are the most widely used electronic nicotine delivery systems and are designed to imitate smoking and aid in smoking cessation. Although the number of e-cigarette users is increasing rapidly, especially among young adults and adolescents, the potential health impacts and biologic effects of e-cigarettes still need to be elucidated. Our previous study demonstrated the cytotoxic effects of electronic liquids (e-liquids) in a human middle ear epithelial cell (HMEEC-1) line, which were affected by the manufacturer and flavoring agents regardless of the presence of nicotine. In this study, we aimed to evaluate the gene expression profile and identify potential molecular modulator genes and pathways in HMEEC-1 exposed to two different e-liquids (tobacco- and menthol-flavored). HMEEC-1 was exposed to e-liquids, and RNA sequencing, functional analysis, and pathway analysis were conducted to identify the resultant transcriptomic changes. A total of 843 genes were differentially expressed following exposure to the tobacco-flavored e-liquid, among which 262 genes were upregulated and 581 were downregulated. Upon exposure to the menthol-flavored e-liquid, a total of 589 genes were differentially expressed, among which 228 genes were upregulated and 361 were downregulated. Among the signaling pathways associated with the differentially expressed genes mediated by tobacco-flavored e-liquid exposure, several key molecular genes were identified, including IL6 (interleukin 6), PTGS2 (prostaglandin-endoperoxide synthase 2), CXCL8 (C-X-C motif chemokine ligand 8), JUN (Jun proto-oncogene), FOS (Fos proto-oncogene), and TP53 (tumor protein 53). Under menthol-flavored e-liquid treatment, MMP9 (matrix metallopeptidase 9), PTGS2 (prostaglandin-endoperoxide synthase 2), MYC (MYC proto-oncogene, bHLH transcription factor), HMOX1 (heme oxygenase 1), NOS3 (nitric oxide synthase 3), and CAV1 (caveolin 1) were predicted as key genes. In addition, we identified related cellular processes, including inflammatory responses, oxidative stress and carcinogenesis, under exposure to tobacco- and menthol-flavored e-liquids. We identified differentially expressed genes and related cellular processes and gene signaling pathways after e-cigarette exposure in human middle ear cells. These findings may provide useful evidence for understanding the effect of e-cigarette exposure.

Patent evaluation of US2019338018 (A1) 2019-11-07 (antibody fragments for the treatment of biofilm-related disorders).

INTRODUCTION: To date, microbial infections are also difficult to eradicate due to the increasing capability of bacteria to form a biofilm. In the era of antibiotic resistance, antibody-based approaches represent great promise in curing infective pathogens. The authors of US2019338018 patent propose a method for the treatment of biofilm-related disorders by using specific antibody fragments. AREAS COVERED: The US2019338018 patent reports antibody fragments, pharmaceutical composition that contains it, and their application for the treatment of biofilm-linked disorders. Proof concept and preclinical results show that mAb mIhfB4NTHI Fab caused robust eradication of the biofilm in the middle ear lumen of chinchillas affected by Hemophilus influenzae infection. EXPERT OPINION: Fab fragments of the US2019338018 patent are new in a general concept to treat bacterial biofilms and biofilm-linked disorders. However, pre-clinical data are only shown for the treatment with Fab fragments of infections caused by H. influenzae in the middle ear of chinchillas. There are no clinical trials that demonstrate that the treatment with Fab fragments may induce a disruption of biofilm produced by H. influenzae or other pathogens and an anti-inflammatory response in infected patients.

Direct Delivery of Antisense Oligonucleotides to the Middle and Inner Ear Improves Hearing and Balance in Usher Mice.

Usher syndrome is a syndromic form of hereditary hearing impairment that includes sensorineural hearing loss and delayed-onset retinitis pigmentosa (RP). Type 1 Usher syndrome (USH1) is characterized by congenital profound sensorineural hearing impairment and vestibular areflexia, with adolescent-onset RP. Systemic treatment with antisense oligonucleotides (ASOs) targeting the human USH1C c.216G>A splicing mutation in a knockin mouse model of USH1 restores hearing and balance. Herein, we explore the effect of delivering ASOs locally to the ear to treat hearing and vestibular dysfunction associated with Usher syndrome. Three localized delivery strategies were investigated in USH1C mice: inner ear injection, trans-tympanic membrane injection, and topical tympanic membrane application. We demonstrate, for the first time, that ASOs delivered directly to the ear correct Ush1c expression in inner ear tissue, improve cochlear hair cell transduction currents, restore vestibular afferent irregularity, spontaneous firing rate, and sensitivity to head rotation, and successfully recover hearing thresholds and balance behaviors in USH1C mice. We conclude that local delivery of ASOs to the middle and inner ear reach hair cells and can rescue both hearing and balance. These results also demonstrate the therapeutic potential of ASOs to treat hearing and balance deficits associated with Usher syndrome and other ear diseases.

Comparison between in vitro toxicities of tobacco- and menthol-flavored electronic cigarette liquids on human middle ear epithelial cells.

Since electronic-cigarettes (e-cigarettes) are considered less toxic than conventional tobacco smoking, the use of e-cigarettes has increased, and the market for e-cigarette liquids (e-liquids) is continuously increasing. However, many studies showed that e-cigarettes may cause various harmful effects in lung, oral and heart. In this study, we investigated the effects of e-liquids on otitis media (OM) using human middle ear epithelial cells (HMEECs). Menthol-flavored e-liquid induced significant cell death in HMEECs (IC50: 1.45 ± 0.14%) and tobacco-flavored e-liquid led to increase in inflammatory cytokine levels and higher mucin production. Flavored e-liquids decreased the mRNA levels of genes encoding epithelial sodium channels (ENaCs) in HMEECs. Apoptosis and autophagy reactions were induced by exposure of HMEECs to menthol- and tobacco-flavored e-liquids. Tobacco-flavored e-liquids caused a greater increase in the levels of autophagosome marker, LC3-II, compared to menthol-flavored e-liquids, which was followed by cell death. These results demonstrate that flavored e-liquids cause cytotoxicity via apoptosis, autophagy, inflammatory response, and mucin production in HMEECs. The flavors present in e-liquids might be a risk factor for the development of otitis media.

Vinpocetine Suppresses Streptococcus pneumoniae-Induced Inflammation via Inhibition of ERK1 by CYLD.

Otitis media (OM) is the most common bacterial infection in children. It remains a major health problem and a substantial socioeconomic burden. Streptococcus pneumoniae (S. pneumoniae) is one of the most common bacterial pathogens causing OM. Innate inflammatory response plays a critical role in host defense against bacterial pathogens. However, if excessive, it has a detrimental impact on the middle ear, leading to middle ear inflammation, a hallmark of OM. Currently, there has been limited success in developing effective therapeutic agents to suppress inflammation without serious side effects. In this study, we show that vinpocetine, an antistroke drug, suppressed S. pneumoniae-induced inflammatory response in cultured middle ear epithelial cells as well as in the middle ear of mice. Interestingly, vinpocetine inhibited S. pneumoniae-induced inflammation via upregulating a key negative regulator cylindromatosis (CYLD). Moreover, CYLD suppressed S. pneumoniae-induced inflammation via inhibiting the activation of ERK. Importantly, the postinfection administration of vinpocetine markedly inhibited middle ear inflammation induced by S. pneumoniae in a well-established mouse OM model. These studies provide insights into the molecular mechanisms underlying the tight regulation of inflammation via inhibition of ERK by CYLD and identified vinpocetine as a potential therapeutic agent for suppressing the inflammatory response in the pathogenesis of OM via upregulating negative regulator CYLD expression.

Otomycosis With Tympanic Membrane Perforation: A Review of the Literature.

OBJECTIVE: The purpose of the present study was to assess the rate of tympanic membrane perforation in patients with otomycosis and to discuss the literature regarding the difficulties in managing this condition. DATA SOURCES: Literature review from 1999 to 2019, Web of Science, PubMed, and Medline. STUDY SELECTION: We searched for eligible articles concerning the clinical entity of tympanic membrane perforation secondary to otomycosis. Case series and clinical trials were the types of articles included for this review. DATA EXTRACTION: All the articles described in the study selection were used for this review. DATA SYNTHESIS: Statistical techniques were not used. CONCLUSION: Based on the available literature, it seems that tympanic membrane perforation secondary to otomycosis is not uncommon. The presence of this complication is associated with 2 problems: Antimycotic solutions are irritant to middle ear and may be ototoxic to the cochlea. Although most cases of fungus caused tympanic membrane (TM) perforation resolve with proper medical treatment, in a few patients a tympanoplasty may be required.

Measuring the middle-ear reflex: A quantitative method to assess effects of industrial solvents on central auditory pathways.

Volatile organic solvents are frequently present in industrial atmospheres. Their lipophilic properties mean they quickly reach the brain following inhalation. Acute exposure to some solvents perturbs the middle ear reflex, which could jeopardize cochlear protection against loud noises. As the physiological mechanisms involved in this protective reflex are highly complex, in vivo rodent models are required to allow rapid and reliable identification of any adverse effects of solvents on the middle ear reflex (MER). In this study, MER amplitude was measured in anesthetized Brown-Norway rats by monitoring the decrease in distortion product otoacoustic emissions (DPOAEs) caused by a contralateral stimulation. Our screening test consisted in measuring the impact of inhalation of solvent vapors at 3000 ppm for 15 min on the MER amplitude. We had previously studied a selection of aromatic solvents with this model; here, we extended the analysis to volatile compounds from other chemical families. The results obtained shed light on the mechanisms involved in the interactions between solvents and their neuronal targets. Thus, benzene and chlorobenzene had the greatest effect on MER (≥ + 1.8 dB), followed by a group composed of toluene, styrene, p-xylene, m-xylene, tetrachloroethylene and cyclohexane, which had a moderate effect on the MER (between + 0.3 and + 0.7 dB). Finally, trichloroethylene, n-hexane, methyl-ethyl-ketone, acetone, o-xylene, and ethylbenzene had no effect on the MER. Thus, the effect of solvents on the MER is not simply linked to their lipophilicity, rather it depends on specific interactions with neuronal targets. These interactions appear to be governed by the compound's chemical structure, e.g. the presence of an aromatic ring and its steric hindrance. In addition, perturbation of the MER by a solvent is independent of its toxic effects on cochlear cells. As the MER plays a protective role against exposure to high-intensity noises, these findings could have a significant impact in terms of prevention for subjects exposed to both noise and solvents.

Fabrication of levofloxacin polyethylene glycol decorated nanoliposomes for enhanced management of acute otitis media: Statistical optimization, trans-tympanic permeation and in vivo evaluation.

Acute otitis media (AOM), an infection in the middle ear, is usually treated through systemic administration of antibiotics because the stratum corneum of the intact tympanic-membrane (TM) possesses low permeability that holds against the ototopical antibiotics use. Therefore, the objective of this work was to encapsulate levofloxacin (LFX) into polyethylene glycol 400 (PEG 400) decorated nanoliposomes (PNLs) as an approach for drug delivery through the intact tympanic-membrane. LFX loaded-PNLs were primed by ethanol injection technique. A 23 full factorial design, using Design-Expert® software, was developed to optimize formulation variables. Particle size, polydispersity index, zeta potential and entrapment efficiency percent of the formulae were determined. The optimal formulation (F7, prepared using 30:1 phospholipid to drug weight ratio, 30 mg cholesterol and 125 mg PEG 400) exhibited improved ex vivo trans-tympanic permeation compared to nanoliposomes lacking PEG 400 and drug solution. In addition, F7 showed greater extent of in vivo deposition of LFX in the intact TM compared to drug solution. Furthermore, in vivo histopathological examination proved the tolerability of the PNLs after ototopical application. Overall, the obtained results revealed that PNLs could be promising for LFX delivery through intact TM providing means for the ototopical drug application for treatment of acute middle ear infections.

Gentamicin delivery to the inner ear: Does endolymphatic hydrops matter?

INTRODUCTION: Middle ear application of gentamicin is a common medical treatment for uncontrolled Ménière's disease. The objective of the study was to evaluate the impact of endolymphatic hydrops on inner ear delivery. METHODS: Perilymph gentamicin concentrations and correlation with endolymphatic hydrops in an animal model were assessed. A group of 24 guinea pigs was submitted to surgical obstruction of the endolymphatic sac and duct of the right ear. Gentamicin was applied either to the right ear's round window niche or through a transtympanic injection. Perilymph specimens were collected at different times. Histologic morphometry was used to evaluate both turn-specific and overall hydrops degree. RESULTS: In animals with endolymphatic hydrops, lower concentrations of gentamicin were observed after 20 or 120 minutes of exposure and in both types of administration, when compared to controls. This difference reached statistical significance in the round window niche application group (Mann-Whitney, p = 0,007). A negative correlation between perilymphatic gentamicin concentration and hydrops degree could be observed in both groups, after 120 minutes of exposure (Spearman correlation, round window niche p<0,001; TT p = 0,005). CONCLUSIONS: The study indicates that the endolymphatic hydrops degree has a negative interference on the delivery of gentamicin into the inner ear following middle ear application.

Does intratympanic xylitol administration have ototoxic effects in a mouse ear model?

OBJECTIVE: To research the ototoxicity of xylitol after intratympanic injection in mice ear model. METHODS: 24 female mice Balb/c mice (48 ears) included in the study. The mice were divided into 4 groups as 6 mice were found (12 ears) in each group. Solutions of 0.9% NaCl solution (Group A), 155 mg/ml (Group B), 310 mg/ml (Group C) and 620 mg/ml (Group D) xylitol, were applied into the middle ear cavity. Microscopic ear examination and auditory brainstem response test were done for each mouse before application of xylitol and on the 1st, 3rd and 10th day of injection. RESULTS: There are some statistically significant alterations found in the threshold values at 8000, 12000, 16000, 24000 Hz frequencies when each group were compared in itself on day 0, 1,3 and 10, which were independent from the increasing dosage. CONCLUSION: According to our findings intratympanic xylitol injection does not have any ototoxic effect in the inner ear. To evaluate the effects of xylitol more clinical studies are need to carried out.

The ineffectiveness of applying moisture to the ear on the incidence and severity of otic barotrauma for air passengers.

OBJECTIVE: The application of moisture to the ear is anecdotally claimed to relieve the pain from otic barotrauma that can arise during aircraft descent. This claim was tested in a randomised double-blind study on an aircraft with eight participants heavily predisposed to barotrauma. METHODS: On the outward flight, half the participants wore 'active' devices that applied moisture to the external ear; the remainder wore placebo devices that contained no moisture, but were otherwise identical. On the return flight, the groups were reversed. Participants wore the devices from just before descent until landing, unless they experienced symptoms of barotrauma, in which case they switched to what they knew was an active device. RESULTS: There were no significant differences between conditions regarding the appearance of the tympanic membrane on landing or the discomfort levels immediately before and after any switch. CONCLUSION: Applying moisture is ineffective for passengers heavily predisposed to otic barotrauma.

A Clinical Trial of Proton Pump Inhibitors to Treat Children with Chronic Otitis Media with Effusion.

OBJECTIVE: Gastroesophageal reflux (GER) is considered a cause of otitis media with effusion (OME). This study aimed to investigate whether OME can be effectively treated with a proton pump inhibitor (PPI), therefore implicating GER as a causative factor of OME. MATERIALS AND METHODS: A PPI or placebo was randomly administered to enrolled subjects for 4-8 weeks. To monitor effusion status, subjects underwent monthly pneumatic otoscopy and acoustic reflectometry. At enrollment and at completion of treatment, subjects underwent an audiogram and tympanogram for assessing changes in hearing due to altered fluid levels in the middle ear. After the treatment period, tympanostomy tube placement was recommended for subjects with unresolved effusion. RESULTS: This study enrolled 16 patients with an average age of 5.17 years. Between the treatment and placebo groups, there was no significant difference in the need for tympanostomy tubes. At completion of this study, patients receiving Lansoprazole demonstrated a significant improvement in pure tone average (p<0.01) and speech recognition thresholds (p=0.04). Four patients (25%) from the cohort dropped out of the study. Eight patients (50%) from the cohort required tympanostomy tube placement. CONCLUSION: Owing to difficulties with recruitment and small sample size, this study was unable to demonstrate the use of PPI in treating OME. A larger study is needed for further evaluation of this process.

The anti-inflammatory effects of erythromycin, clarithromycin, azithromycin and roxithromycin on histamine-induced otitis media with effusion in guinea pigs.

BACKGROUND: Otitis media with effusion is a clinical manifestation characterised by inflammation of middle-ear mucosa. This study investigated the therapeutic effect of erythromycin, clarithromycin, azithromycin and roxithromycin on a histamine-induced animal model of otitis media with effusion. METHODS: The animals were divided into five groups, receiving erythromycin, clarithromycin, azithromycin, roxithromycin or saline solution. The guinea pigs in the study groups received erythromycin (40 mg/kg/day), clarithromycin (15 mg/kg/day), azithromycin (10 mg/kg/day) or roxithromycin (10 mg/kg/day) for 3 days by gastric tube. Four hours after the end of the administration, histamine solution was injected into the right middle ear. RESULTS: The lowest neutrophil density value obtained using stereological techniques was in the azithromycin group (0.86 ± 0.25 × 10-5/µm3), while the highest value was observed in the control group (6.68 ± 3.12 × 10-5/µm3). The anti-inflammatory properties of clarithromycin, azithromycin and roxithromycin were similar to one another, but better than that of erythromycin. CONCLUSION: The use of macrolide antibiotics is recommended, as they show antibacterial and anti-inflammatory efficacy in otitis media with effusion.

Eosinophilic Otitis Media Treated with Anti-IgE Monoclonal Antibodies and A Bone Conduction Implant.

Eosinophilic otitis media (EOM) are intractable otitis media characterized by highly viscous secretions containing eosinophils in the middle ear. They are resistant to conventional medication and surgery. This condition occurs primarily in patients with bronchial asthma or allergic rhinitis and is often complicated by rhinosinusitis. Systemic and topical steroid therapies are effective treatments. However, long-term steroid therapy is often limited by a high risk of serious adverse effects. The use of topical steroids and otorrhea are bothersome when wearing hearing aids. Here, we report a case of intractable otitis media due to EOM. Otorrhea was controlled with topical steroids. Bone conduction hearing was stable for an extended period with anti-IgE monoclonal antibodies (omalizumab). An implantable bone conduction hearing aid was used for rehabilitation of conductive hearing loss.

Systematic review of ototoxic pre-surgical antiseptic preparations - what is the evidence?

OBJECTIVE: There is uncertainty regarding the safety of surgical antiseptic preparations in the ear. A systematic review of the literature was conducted to assess the evidence regarding ototoxicity of surgical antiseptic preparations. METHODS: A literature search was conducted using the PRISMA methods. Key words included "ototoxicity" "hearing loss", "antiseptic", "surgical preparation", "tympanoplasty", "vestibular dysfunction", "chlorhexidine", "iodine", "povidone", "ethanol", and "hydrogen peroxide" using Medline, Embase, Cochrane Library, Scopus and Web of Science. We included peer-reviewed papers that 1) objectively measured ototoxicity in humans or animals through hearing, vestibular function or histologic examination, 2) studied topically applied surgical antiseptic preparations, 3) were either in English or had an English abstract. We excluded papers that were 1) in vitro studies, 2) ear trauma studies, 3) studies of ototoxic ear drops intended for therapy, or 4) case reports. Studies included in the final review were screened using the PRISMA method. Current systematic review registration number pending: 83,675. RESULTS: Fifty-six papers were identified as using PRISMA criteria. After applying our exclusion criteria, 13 papers met overall study criteria. Of these, six papers reported ototoxicity of iodine based solutions, five papers reported ototoxicity of chlorhexidine and ethanol and two papers assessed hydrogen peroxide. All papers reviewed were animal studies. Iodine based solutions show least harm overall, while chlorhexidine and high concentrations of alcohol based solutions showed most harm. The evidence on hydrogen based solutions was inconclusive. CONCLUSIONS: The overall evidence for anyone antiseptic solution is weak. There is some evidence that iodine, chlorhexidine, hydrogen peroxide and alcohol based antiseptics have ototoxicity. Conclusive evidence for human ototoxicity from any solution is not strong.

Fisetin administration improves LPS-induced acute otitis media in mouse in vivo.

Acute otitis media is one of the most common infectious diseases worldwide in spite of the widespread vaccination. The present study was conducted to explore the effects of fisetin on mouse acute otitis media models. The animal models were established by lipopolysaccharide (LPS) injection into the middle ear of mice via the tympanic membrane. Fisetin was administered to mice for ten days through intragastric administration immediate after LPS application. Hematoxylin and eosin (H&E) staining was performed and the pro-inflammatory cytokines, including interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), IL-6 and VEGF, were measured through enzyme-linked immunosorbent assay (ELISA) method and RT-qPCR analysis. Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway was detected by immunoblotting assays. Reactive oxygen species (ROS) generated levels were determined through assessment of anti-oxidants, and TXNIP/MAPKs signaling pathways were explored to reveal the possible molecular mechanism for acute otitis media progression and the function of fisetin. Fisetin reduced mucosal thickness caused by LPS. In fisetin-treated animals, pro-inflammatory cytokine release was downregulated accompanied with TLR4/NF-κB inactivation. ROS production was significantly decreased in comparison to the LPS-treated group. The TXNIP/MAPKs signaling pathway was inactivated for fisetin treatment in LPS-induced mice with acute otitis media. The above results indicated that fisetin improved acute otitis media through inflammation and ROS suppression via inactivating TLR4/NF-κB and TXNIP/MAPKs signaling pathways.

Electrophysiological and Histopathological Evaluation of Effects of Sodium-2 Mercaptoethanesulfonate Used for Middle Ear Surgery on Facial Nerve Functions.

OBJECTIVE: Sodium-2-mercaptoethanesulfonate (MESNA) is widely used in medicine because of its antioxidant and mucolytic effects. In recent years, it has been used in otologic surgery. Because it cleaves disulfide bonds, it is used to easily dissect the epithelial matrix in cholesteatoma and atelectasis. In this study, we hypothesized that MESNA does not have any toxic effect on the facial nerve, and the effects of MESNA on the facial nerve were examined histologically and electrophysiologically. MATERIALS AND METHODS: Twenty Wistar albino rats were used. Groups A and B were designated as the control and sham groups, respectively. The animals in groups C and D were administered 20% and 50% of MESNA solution, respectively, after the facial nerve was exposed in the parotid region. Electromyography (EMG) measurements were performed preoperatively and postoperatively at 4 weeks. The animals were subsequently euthanized; facial nerve samples were taken for histopathological examination. RESULTS: When EMG parameters were compared within and between each group, preoperative and postoperative results were not statistically significantly different. Histopathological examination showed that MESNA did not cause any inflammation, granulation tissue, or foreign body reaction. CONCLUSION: To the best of our knowledge, the effects of MESNA on facial nerve functions have not been investigated. In this study, the effects of MESNA after direct application to the facial nerve were examined electrophysiologically and histologically, and it was determined that MESNA did not cause any toxic effects. It was concluded that MESNA can, therefore, be safely used during middle ear surgery.